1. Technical Field
The present invention relates to a resonator element, a resonator, an oscillator, an electronic apparatus, and a moving object.
2. Related Art
In a compact information apparatus such as a Hard Disk Drive (HDD), a mobile computer, or an IC card, and in a mobile communication apparatus such as a cellular phone, a car phone, or a paging system, or the like, an electronic device such as a resonator or an oscillator is widely used.
In the related art, an example of a resonator element used in the electronic device is shown in FIG. 31.
In FIG. 31, in a resonator element 101, the shown outline is formed by etching a piezoelectric material such as quartz crystal, and the resonator element includes a rectangular base portion 112 which is mounted on a package (not shown) or the like, and a pair of vibrating arms 120 and 122 which extend upward in the drawing from a main body portion 114 which supports and connects the vibrating arms of the base portion 112. In addition, grooves 128 and 130 and a necessary driving electrode (not shown) are formed on a principle surface (front and rear surfaces) of the vibrating arms.
In the resonator element 101, if a driving voltage is applied via the driving electrode, approaching and separation between tip portions of each of the vibrating arms 120 and 122 are repeated, the tip portions are flexurally vibrated, and thus, a signal of predetermined frequency is extracted.
However, the vibration of the resonator element 101 is propagated to the base portion 112 side according to the flexural vibration of the vibrating arms 120 and 122, and the vibration may be leaked from the base portion 112 to a member (adhesive, metal bump, or the like) which fixes the resonator element. Accordingly, in the resonator element 101, a decrease in a Q value occurs, and as a result, there is a problem that a Crystal Impedance (CI) value is increased.
In order to prevent the problems, in JP-A-2002-261575, a resonator element is disclosed, which has a structure in which notches are formed in a base portion at a position closer to a vibrating arm side than a location fixed to a package or the like.
Moreover, also in JP-A-2005-236563, a resonator element is disclosed, which has a structure in which a through groove is formed at a position closer to a vibrating arm side than a location fixed to a package or the like.
According to effects of the notch or the through groove, the leakage of the vibration from the vibrating arm is decreased, and the leakage of the vibration from the base portion to the member which fixes the resonator element is suppressed.
However, while reduction in the sizes of various apparatuses on which the resonator elements are mounted is progressed, it is necessary to decrease the size of the resonator element itself as much as possible.
Accordingly, in the resonator element disclosed in JP-A-2002-261575 or JP-A-2005-236563, since the notch or the through groove is provided in the base portion and a length of a transmission path of the vibration leakage from the vibrating arm side to the fixed location is lengthened, a length of the resonator element is lengthened, and there is a problem that reduction in the size of the resonator element is difficult to obtain.